Subjective refraction determination instrument - has first lens displaying test figures in focal plane on picture side

摘要

The instrument is used in optometry for subjective determination of refraction, having a first lens (3) displaying optotypes or test figures in its focal plane on the picture side. This is followed by a second lens (4) displaying the test figures to the eye under examination. The distance of the focal point of the second lens on the article side to that of the first lens on the picture side is adjustable, typically with the aid of a third lens unit (6) between the first two. The inlet pupil of the lens system can be in the focal plane of the first lens on the object side.